There are numerous applications in which it is desirable to detect the presence of laser energy. Due to the intensity of this energy, various devices have been proposed. These devices often have application in systems which operate to protect and warn laboratory personnel who function in the vicinity of a laser source. These systems utilize a variety of detection elements including photodetectors, photovoltaic detectors, Golay cell thermocouples, and bolometers. Many of these systems are designed to be light sensitive and to detect laser energy by the particular light characteristics of laser beams. Others are heat sensitive and detect radiation by measuring a temperature-dependent change in resistance.
U.S. Pat. No. 3,898,605 discloses a detection system directed to a temperature sensitive film integral to an infrared waveguide. The system measures changes in resistivity responsive to the heat generated by a parallel beam of laser energy.
U.S. Pat. No. 3,781,748 is directed to a chalcogenide glass bolometer design which utilizes a semiconducting thermistor to indicate the presence of electromagnetic radiation.
While the systems proposed by the prior art have proved satisfactory for some applications, they exhibit shortcomings in various respects. Susceptibility to mechanical damage, difficulty of construction and the necessity of transformer coupling are but some of the limitations which make the prior systems unsuitable for use in a space or military environment.